Network switches provide signal connections between a plurality of input ports and a plurality of output ports. Each network switch typically comprises at least one switch fabric for facilitating these signal connections. The signal connections are made between the switch fabric and the input ports and the output ports.
Each switch fabric is typically located on its own printed circuit board within the network switch. Likewise, any circuitry that is associated with the input ports and the output ports is typically located on separate printed circuit boards within the network switch. A motherboard or backplane is provided in order for the signal connections to be made between the switch fabric and the input ports and the output ports. That is, the backplane provides physical connections between the switch fabric and the input ports and the output ports. It is over these physical connections that the signal connections are made.
Depending on the size of the network switch, it may be required that a large number of signal connections must be made between the switch fabric and the input ports and the output ports, and, correspondingly, a large number of physical connections must be made across the backplane between the switch fabric printed circuit board and the printed circuit board(s) associated with the input ports and the output ports. There are problems associated with such a large number of physical connections being made across a backplane, including printed circuit board area limitations and signal noise interference. Accordingly, it would be beneficial to reduce the number of physical connections that must be made across the backplane between the switch fabric printed circuit board and the printed circuit board(s) associated with the input ports and the output ports, while not reducing the data rate associated with the signal connections.
In addition to the benefit of reducing the number of physical connections between the switch fabric printed circuit board and the printed circuit board(s) associated with the input ports and the output ports, it would also be beneficial to utilize the reduced number of physical connections in a most efficient manner. That is, it would be beneficial to utilize the reduced number of physical connections between the switch fabric printed circuit board and the printed circuit board(s) associated with the input ports and the output ports in an efficient manner so that signal connections may be made to provide for signal redundancy and to compensate for hardware failures. Accordingly, it would be desirable to provide an apparatus and method for efficiently transferring data across a backplane in a network switch.
Some switch devices have plural elements which require access to a switch fabric, yet these elements collectively require an amount of bandwidth which does not exceed the bandwidth provided by a single thread through the switch fabric. Therefore, it would be beneficial to be able to make such network elements share the single thread, while ensuring that their collective bandwidth does not exceed the available thread bandwidth.